Homogenizing unit for paper making machine



Dec. 21, 1965 A. E. H. FAIR 3,224,929

HOMOGENIZING UNIT FOR PAPER MAKING MACHINE Original Filed July 11, 1962 4 Sheets-Sheet 1 INVENTOR.

ALBERT EDWARD HAROLD FAIR ATTORNEY.

Dec. 21, 1965 A. E. H. FAIR 3,

HOMOGENIZING UNIT FOR PAPER MAKING MACHINE Original Filed July 11, 1962 4 Sheets-Sheet 2 INVENTOR. ALBERT EDWARD HAROLD FAIR H BY ATTORNEY.

Dec. 21, 1965 A. E. H. FAIR HOMOGENIZING UNIT FOR PAPER MAKING MACHINE 4 Sheets-Sheet 5 Original Filed July 11, 1962 INVENTOR.

ALBERT EDWARD HAROLD FAIR ATTORNEY.

Dec. 21, 1965 A. E. H. FAIR 3,224,929

HOMOGENIZING UNIT FOR PAPER MAKING MACHINE Original Filed July 11, 1962 4 Sheets-Sheet 4 INVENTOR.

ALBERT EDWARD HAROLD FAIR ATTORNEY United States Patent 3,224,929 HOMOGENIZING UNIT FUR PAPER MAKING MACHINE Albert Edward Harold Fair, 101 Monmouth St, Brookline, Mass.

Original application July 11, 1962, Ser. No. 209,136, new Patent No. 3,135,654, dated June 2, 1964. Divided and this application Mar. 26, 1964, Ser. No. 355,021

3 Claims. (Cl. 162342) This application is a division of application, Serial Number 209,136, filed July 11, 1962, now Patent 3,135,- 654 issued June 2, 1964.

The present invention relates to new and useful improvements and structural refinements in machines of the paper and allied industries and pertains broadly to improved means for handling a stream of a suspension of papermaking fibers with or without other additives in a liquid vehicle. More particularly, it envisions refinements in flow control means allowing a predesigned, uniformly-created, turbulence under a relatively low rate of forward flow at the point of approach to such as the spout or orifice or slice through which the aqueous suspension is delivered to the web-forming component, be it the continuously-traveling endless wire of a Fourdrinier type, the foraminous cylinder mold of a cylinder type, or other appropriate forming means, of a paper-making machine, the invention being not considered as limited to any particular species but rather to any generic type of webforming apparatus.

Herein, by means of rotating homogenizing means, strategically positioned within the head box, the flow from the normally circular-in-cross-section inlet feeding the head box is transformed to a flat and narrow-in-crosssection flow corresponding to that of the flow onto the forming surface, such transformation being effected within a minimum of space and with a minimum degree of surface exposure, while simultaneously, those initial fluctuating longitudinal currents, set up upon head box feeding, are appreciably reduced by the positioning of one of such rotating homogenizing means within what I define as an explosion area immediatley adjacent the inlet wherefor, when the how subsequently expands there from into a main head box area, such initial currents will have been destroyed and the flow will experience a condition of flowing, slowing into a relatively placid pond, fully intentioned in the light of the law of hydraulics which teaches that a placid pond upstream of a uniform orifice will produce a uniform flow downstream of that orifice.

f /here the fluid constitutent water only, the production of such a placid pond would be a relatively simple concern and good flow could be assured with a minimum of effort. But in the contemplated usage, the fluid constituents will include a suspension of fibers, fillers and the like, offering attendant separating out and settling problems unless that fluid is maintained in an active state of agitation.

The state of a placid pond having been attained, such slowing implies a need for a stirring means, if the aims of avoiding settling and flocking are to be served. By the creation of an organized and fine pattern of small intermittent lateral currents within the suspension, I achieve retention of the condition of a placid pond, but with a new internal condition generated within the pond in the form of a pond which is alive so as to permit fiber flow from the orifice in what I define as an organized confusion of currents, in that the fibers cross each other in all directions obviously to produce an all-directional balance of strength in the formed end product.

The key to attaining these ends is the means in the form of a rotating homogenizing roll by which the longitudinal currents are broken up and small and organized cross-currents are induced and further by which the suspension is kept in a state of lively distribution, all thereby to allow a forwardly-flowing constantly-agitated stock stream of a well and uniformly dispersed mixture possessing minimal, if any, forward currents, and being amenable to close and uniform web formation with equalized strength in both forward and cross directions.

With the above and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter described and illustrated in the accompanying drawings wherein are shown several, but not necessarily the only, forms of embodiment of the invention:

FIG. 1 is a broken view, in side elevation, of a homogenizing roll of the invention;

FIG. 2 is a sectional view on the line 2-2 of FIG. 1;

FIG. 3 is a view, in front elevation, of an agitating blade of the homogenizing roll of the invention;

FIG. 4 is a broken view, in side elevation, of a modified form of homogenizing roll of the invention;

FIG. 5 is a sectional view on the line 5-5 of FIG. 4;

FIG. 6 is a sectional view of another modified form of the homogenizing roll of the invention;

FIG. 7 is a sectional view of still another modified form of the homogenizing roll of the invention;

FIG. 8 is a sectional view of a head box or flow box, as viewed from the front or tending side thereof, and illustrating a practical embodiment of the homogenizing roll means of the invention; and

FIGS. 9 and 10 are fragmentary side elevational views of modified forms of a head box, with certain components being shown in section.

The homogenizing unit hereof comprises a longitudinally-extending rotatable cylindrical shaft or piping 10, which is preferably hollow to achieve a reduction in weight, with an outwardly-projecting solid trunnion or journal 12 receivable in a head 14 at each of its opposite ends, each trunnion being insertable throughv the respective adjacent head box side wall in suitable journal or bearing means mounted in said side wall whereby the homogenizing unit may be positioned between and intercoupled with the headbox side walls in close-running relationship therewith.

On the outer peripheral surface of shaft 10, a multiplicity of radially-arranged outwardly-extending agitator blades or fins or vanes 16 are stationarily secured, each such agitator blade being disposed angularly or obliquely relative to the longitudinal shaft axis according to a predetermined pattern.

The agitator blades are each profiled as shown in FIG. 3 and when fixedly mounted in spaced relation upon shaft 10, are pitched so as to be helicoidally directed.

The blades are arranged as groupments or sets, the blades of each groupment or set being arranged in a longitudinally-extending row in equi-spaced distance from each other and parallel relationship as to each other, with the axis of the row being parallel to the longitudinal axis of the shaft.

A plurality of such rows, equidistant from each other around the shaft periphery, divide the surface area of the shaft into a plurality of substantially equal segmental sections. That is, the rows, 4 in number in the illustrated embodiment, are preferentially equidistant from each other, they being disposed approximately from each other, though it will be understood that the number of rows can be varied so that the angle there'oetween may be greater than or less than said 90.

Each blade of each row encompasses a divergence angle by virtue of its oblique disposition relative to the shaft axis. The divergence angle preferentially will be not more than 80 and not less than 60 relative to the longitudinal shaft axis. It will be understood, however, that the divergence angle could be anything between 45 and 89 The blades of one row and the blades of the next adjacent rows are disposed at opposing angles so that they form angularly-intersecting planes as the shaft is rotated whereby, in operational use, to effectuate opposing sets of miniature or localized cross-currents. The set of such miniature or localized cross-currents enduced by the blades of one axial row are opposed by the set of miniature or localized cross-currents enduced by the blades of the next adjacent axial row so as to allow a back-andforth movement, which is repeated over and over as the shaft is rotated. That is, the suspension is motivated generally in one direction by one set of blades (the blades of one row) and is pushed in another direction by the next adjacent set of blades.

Simultaneously, diametrically opposite to the set of blades of a row at any point directing the suspension in one direction, there is another set of blades directing the flow in the same direction, again tending to create these aforedescribed opposing forces.

It is in this manner that a shearing action ensues, causing the stock to be deflected, first in one direction and then in a direction opposite thereto in a rapid pulsating manner so as to allow complete overlapping and intermingling by way of repetitive swirls, while simultaneously avoiding stock floculation and minimizing the development of erratic eddy currents and other non-uniform flow conditions.

Such repetitive reversing of cross currents serves to mix the stock and to reorient the fibers so that many of them will have their longitudinal axes at right, or approximately right, angles to the direction of flow instead of being aligned with the flow, as is normal, thereby serving the aforedescribed function of equalizing directional strength.

As the shaft is rotated within a single 360 cycle, the blades move so as to create a wobble action in the stock, that is, the stock is impelled first in one direction and then in another so that the flow is transversely broken into a plurality of exceedingly fine cross currents. The blades rotate to impart a wobble effect to the stream as it flows between the blades and then flows into and merges with adjacent eddys to affect the ultimate desired interweaving and uniform fiber distribution. By such rotative movement, any shive problem, wherein the fibers tend to deposit and to string on the blades and the shaft, is precluded.

The blades cause this wobbling effect as they each ro tate about the axis of the shaft and thus produce a fine pattern of rapidly recurring and reversing currents. Thereby they effectuate a random distribution of the fibers uniformly and evenly at all points throughout the shaft length as the converging streams intermingle upon having passed between the blades of a set and preliminary to passing between the blades of the next adjacent set.

It is contemplated that not only the pitch but also the dimensions of the blades may be varied to satisfy specific requirements of use.

Preferentially, the blades will be of a thickness not less than A3" and may be considerably thicker. Also preferentially, the depth of the blades will be in excess of one half the diameter of the supporting shaft.

The shaft may be rotated at any one of a wide range range of speeds depending upon the work expected thereof; it has been found practical to operate same at speeds within the range of 30 to 300 rpm.

The shaft and blade assemblage may be used as a single unit, or a plurality of such assemblages may be cooperatively employed in an aligned relationship, as will be hereinafter observed.

A modified form of homogenizing roll is shown in FIGS. 4 and 5 wherein a cylindrical shaft or piping 110, with outwardly-projecting solid trunnions or journals 112 each receivable in a head 114- at one of its opposite ends is mounted relative to the side wall so that the homogenizing unit may be positioned between the headbox side walls.

On the outer peripheral surface of shaft 110, a multiplicity of radially-arranged outwardly-extending agitator blades or fins or vanes 116 are stationarily secured in spaced relationship, each such agitator blade being disposed angularly relative to the longitudinal shaft axis.

The agitator blades are each pitched so as to be helicoidally directed and are arranged as groupments, the blades of each groupment or set being arranged in a longitudinally-extending roW in a parallel relationship and equi-spaced distance from each other, with the axis of a row being parallel to the longitudinal axis of the shaft and with a plurality of such rows being equidistant from each other around the shaft periphery to divide the surface area of the shaft into a plurality of substantially equal segmental sections.

Between each of the adjacent blades of two of the diametrically-opposed groupments or sets and extending coplanar and inparallelism therewith a smaller radially- .arranged outwardly-extending agitator blade or fin or vane 117 is stationarily secured upon shaft and likewise pitched so as to be helicoidally directed.

The blades 116 of one axial row and the blades 116 and 117 of the next adjacent axial rows are disposed at opposing angles so that they form .angularly-intersecting planes as the shaft is rotated. Operationally, such arrangement etfectuates opposing sets of miniature or 10- calized cross-currents. The set of miniature cross-currents enduced by the blades of one row being opposed by the set of miniature cross-currents enduced by the blades of the next adjacent row so as to allow a backand-forth repetitive movement as the shaft is rotated, the suspension being motivated generally in one direction by the blades of one row and in another direction by the blades of the next adjacent row in a pulsating manner to allow complete overlapping and intermingling, such repetitive reversing of cross currents serving to mix the stock.

In the embodiment shown in FIG. 6, a homogenizing unit with six rows of blades 16' is disclosed and in the embodiment shown in FIG. 7 a homogenizing unit with eight rows of blades 16" is disclosed.

As illustrative of a practical embodiment of a plurality of the homogenizing units Within an actual head box, reference is now made to FIG. 8 wherein is shown a head box, generally indicated by numeral 20, cooperant with a delivery section, generally indicated by 22, and including an outflow end 24 suitably coupled as by its flange 26 to the inlet flange 28 of the head box with suitable gasket means interposed therebetween.

The delivery section accommodates the stock in its floW toward the head box, the flow being effected by conventional flowing means (not shown).

Headbox 20 comprehends a pair of transversely-spaced vertically-extending side walls 30 and interconnected transversely-spaced forward and rearward end walls 32 and 34 respectively and a bottom wall 36 and an apron wall 38 to define a pond therewithin.

Preferentially, but not obligatorily, the apron wall will be provided with a contoured rearmost portion 39, as shown, for purposes to be referred to.

It is known that a large quiet headbox will eliminate currents but will allow the fibers a freedom of expression of an inherent tendency to coagulate. A smooth flow at relatively slow speed, with the fibers at rest relative to one another, is known to allow conditions that promote flocculation, slime formation, and stock accumulation in dead spots. Contrariwise, a strong irregular agitation, while mixing the fibers throughly and dispersing them, will create the very objectionable cross currents, surges and eddies I seek to avoid with this invention.

The head box design hereof, accordingly, is a compromise between these two extremes and comprehends cooperant homogenizing devices to promote the required agitation so as to disperse the fibers in the fulfillment of the desiderata of allowing no surging at the head box entrance, allowing no dead areas within the head box, allowing no stangnant corners or sharp angles, allowing a uniform delivery to the slice, achieving a uniform and homogeneous fiber dispersion, eliminating any entrained air, and precluding fiber flocculation.

The lower portion of rearward end Wall 34 is configured cooperantly with bottom wall 36 to define a lowermost restricted opening 40 leading inwardly into the head box from the inlet thereof.

Extending upwardly therefrom and defined by the inclining upwardly and outwardly portions of walls 34 and 36 is a passageway 42 of gradually increasing length or depth, as contrasted with the lateral widthwise dimension, for accommodating the upward stock flow, which upward flow will achieve a general slowing of flow, with the walls themselves constituting one set of interference devices for promoting the desired agitation means for preventing the floc formation.

A homogenizing unit, designated generally as A, is disposed within the area defined by the jointure of lowermost restricted opening 40 and passageway 42 in manner such as to extend transversely of the path of stock flow and in slightly spaced relation from said walls 34 and 36 so as to impart to the flowing stock such motion as will insure the desired good agitation, overcome stagnation, and offset any tendency of the stock to settle along walls 34 and 36.

Preferentially, but not obligatory, homogenizing unit A will rotate against the flow in the direction indicated by arrow a.

During the flow through the ever-widening passageway 42 thereabove, the suspension is subjected to further agitation and mixing by a plurality of homogenizing units, designated generally as B, disposed in alignment as to each other in a plane angularly related to the horizontal axis of the stock in the pond thereabove.

As shown, one agitating unit may be disposed slightly behind the other so that the flow will meet resistance in the shorter path and avoid a tendency to short circuit the wide path to the slice.

A rotative movement is imparted to each agitating unit by power means, not shown. Preferably, the rolls adjacent the walls are rotated in the direction indicated by arrows b so as to wash the walls clean and in timed relation to the rate of flow though they may be rotated at varying rates of speed so that they may be rotated unisonly or out of unison and at constant or at variable speeds.

The main point is that they serve to effectuate a slowing of the flow from the homogenizing unit A to the top of the pond indicated by P so as to achieve a placid pond and thereby to lose any straying velocities.

In the case of homogenizing unit B, the velocities are quickly damped out.

As is conventional, a slice, generally indicated by 50, is provided for the primary function of delivering a sheet of liquid of uniform thickness and equal velocity across the width of the web-forming component. On a cylinder machine the bafiles or control wings substitute for the slice.

Vertical movement of a slice lip 52 is achieved by such as a hand wheel 54 and related instrumentalities suitably supported relative to the head box walls, all so as to increase or decrease the height of the slice opening.

A breast roll 56 is disposed adjacent apron board 38 and an endless wire 58 is entrained therearound, all in known maner to define the web-forming component.

For a given grade or type of paper, operation must be such as to deliver a consistent amount of fibers to the web-forming component. The amount of water accompanying the fibers may be varied to control the formation and/ or change the qualities of the finished Web. In other words, the consistency (pounds of fiber/ pounds of water) in the head box can be varied, and the adjustment of the slice will allow a constant head to be maintained.

The homogenizing units, so disposed, generally comprehend an arrangement designed to keep the pond alive, to eliminate flocking, to destroy objectionable currents, and to prepare the stock for delivery through the slice by providing means whereby the stock stream meets identical resistance across the entire head box width and is evenly fed to the forming surface at a single, selected velocity. Simultaneously therewith, I cure other specific prior art defects inclusive of the formation of light and heavy streaks running in the machine direction at regular or varying spaced intervals across the machine width by the deliberate and intentional creation of an aforedescr-ibed pattern of a multiplicity of minute cross currents for effecting improved a random dispersion of the fibers.

As known, a momentary speed increase followed by a sudden speed decrease creates small eddy currents which break up fiber fiocs.

The homogenizing units hereof effectuate a reduction in area through which the fluid flows.

At the point of reduced area, the stock velocity is increased and upon moving past the homogenizing unit, the velocity of stock and Water is again decreased.

With continued reference now to the drawings, and with reference to another embodiment of the invention for purposes of disclosure, I have shown, in FIG. 9, the outflow end of a delivery section, generally indicated by reference numeral 222, for directing a flow of stock to a head box, generally indicated by reference numeral 226 mounted adjacent the path of movement of the Fourdrinier wire in the known manner.

The delivery section includes an outflow end 224 suitably coupled as by its flange 226 to the inlet flange 223 of head box 220 and accommodates the stock in its flow toward the head box.

Conveniently, the opening of the inlet or inflow end is circular, though it may be square or rectangular or otherwise, to accommodate itself to the particular configuration which the inflow conduit may partake of. The orifice at the slice being essentially in the form of a rectangle, it is the desideratum to convert the flow from the round cross section of the feeder pipe to a rectangular cross section by the system now to be described.

Head box 220 comprehends a pair of transverselyspaced vertically-extending side Walls 239 and interconnected transversely-spaced forward end wall (not shown) and rearward end wall 234 and a bottom wall 236 and an apron wall 238 to define a pond therewithin.

inwardly of inlet flange 228, the inlet passageway is defined by the generally horizontally-extending verticallyspaced wall portions 241 and 243 of the lower extremities of rearward end wall 234 and bottom wall 236 respectively.

Wall member 241 is provided with an arcuate portion 245 so as to provide an enlarged area of the passageway within which a homogenizing unit, delineated by A, is disposed so as to extend transversely of the path of stock ilow and in slightly spaced relation from walls 241 and 243 so as to impart to the flowing stock the aforedescribed motion.

Said homogenizing unit A serves to destroy longitudinal currents to insure good agitation, to overcome air pockets, and to offset any tendency of the stock to hug the walls 241 and 243 as well as the other walls subsequently to be defined.

In effect, the enlarged portion of the passageway defines an explosion chamber, with controlled internal action or controlled force using as the explosive force pressures of such low degree that the fibers of the stock being conditioned are neither seriously damaged physically nor importantly altered chemically.

The fluid of relieved-pressure flows into a passageway 242 defined by the adjacent portions of walls 234 and 236. Said passageway is of gradually-increasing length or depth as contrasted with its lateral widthwise dimension to allow upward stock flow which achieves a general slowing reaction. That is, the walls 234 and 236 are so related that each generally diverges from the other so as to provide therewithin said passageway 142 which gradually widens in depth (as contrasted with width) from its lowermost area towards its uppermost area so as to allow a gradually decreasing resistance to flow and a uniform spreading out of the stock.

During the flow through the ever-widening passageway 242, the suspension is subjected to further agitation and mixing by a plurality of aligned homogenizing units, designated generally as B, disposed in an angular plane as respects the surface of the pond.

Said agitating units may be mounted at their opposite ends upon plates 251 each mounted on a side wall 230 and being selectively positionable relative thereto as by sets of openings 253 through which suitable bolting means may be extended so as desirably to position the p ate relative to the side wall in a selective manner according to the degree of angularization preferred.

The agitating units are thereby disposed transversely of the path of stock flow through the head box and in spaced relation to the discharge outlet thereof adjacent the forming medium so as to attain a passive direction or redirection of flow, to keep the pond alive and to destroy the objectionable currents.

With continued reference now to the drawings, and with particular reference to still another embodiment of the invention for purposes of disclosure, I have shown, in FIG. 10, the outflow end of a delivery section comprising an inflow conduit 322 for directing a flow of stock to a head box 320 mounted adjacent the path of movement of the Fourdrinier wire. The delivery section includes an outflow end 324, suitably flanged to the head box inlet 341.

Normally, the opening of the inlet or inflow end will be circular, though it may be square or rectangular or otherwise configured, to accommodate itself to the particular dimensions which the inflow conduit may partake of.

The orifice at the slice being essentially in the form of a rectangle, it is the desideratum to convert the flow from the round cross section of the delivery section to a rectangular cross section by the system now to be described.

Head box 320 comprehends a pair of transverselyspaced vertically-extending side walls 350 and interconnected transversely-spaced forward end wall (not shown) and rearward end wall 334 a bottom wall 336, and an apron wall 358 to define a pond therewithin.

Inlet passageway 341 is defined by the vertically-extending horizontally-spaced Wall portions of the lower extremities of rearward end wall 334 and bottom wall 336 respectively, the bottom wall 336 being provided with an arcuate portion 345 so as to provide an enlarged area of the passageway (explosion chamber) within which a homogenizing unit, delineated by A", is disposed in manner so as to extend transversely of the path of stock flow and in slightly spaced relation from the walls, thereby to impart the aforedescribed motion to the flowing stock, and to insure good agitation, to overcome stagnation, and to offset any tendency of the stock to hug the head box walls.

Extending upwardly from the explosion chamber and defined by the inclined portions of walls 334 and 336 is a passageway 342 of gradually increasing length or depth, as contrasted with the lateral widthwise dimension for the upward stock flow, which upward flow allows an elimination of air from the stock and achieves a general flow slowing of flow. That is, the Walls 334 and 336 are so related that each generally diverges from the other so as to provide therewithin a passageway which gradually widens in depth (as contrasted with width) from its lowermost area towards its uppermost area so as to allow a gradually decreasing resistance to flow. Such divergence of the walls achieves an effect which allows the suspension to spread out toward the sides of the passageway rather than to tend to concentrate centrally thereof, as would be the case were the resistance to How not so decreased.

By such structure, the stock is constrained to flow vertically upwardly through the defined passageway, the chamber having an ever-widening front to rear dimension or width. Therewith, I allow a capacity for gradually and progressively converting a flow of circular cross section upon entry into the head box into a constantly widening and slowing stream which slowly transforms to a flow of generally rectangular cross section corresponding to the lateral width of the slice and web forming component.

During the flow through the ever-widening passageway 342, the suspension is subjected to further agitation and mixing by a plurality of aligned homogenizing units, designated generally as B", disposed in a plane angulanly related to the surface of the pond as above described.

Without further analysis, the foregoing is intended to so fully reveal the gist of my invention and the construction and operation of the device thereof that others can, by applying current knowledge, readily adapt it for various applications without omitting features which, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. The substitution of equivalents and other modifications are contemplated, as circumstances may suggest or render expedient, since the invention is susceptible of various changes and modifications without departing from the real spirit or underlying principles of the invention. In other words, it is not desired to limit the invention to the exact construction shown and described as the objects of the invention may be attained by the use of constructions different in certain respects from that disclosed.

The following claims are desired to include within the scope of the invention all such suitable variations, modifications and equivalents by which substantially the results of the invention may be obtained through the use of substantially the same or equivalent devices or means.

Accordingly, limitation of this invention should be made only as determined by a proper interpretation of the terms used in the subjoined claims.

It is intended to claim the invention, broadly as well as specifically, as indicated by the appended claims.

What is claimed as new and useful is:

1. In a papermaking machine, a homogenizing unit disposable within a flow box for producing organized cross currents for dispersing the fibers in a flow box flow stream comprising, a rotatable roll disposed in spaced relationship transversely of the flow stream in the head box, a plurality of vanes rigidly fixed upon said roll and arranged in parallelism oblique to the longitudinal axis of said roll and axially spaced therealong as sets in rows equi-distant from each other, with the vanes of a row being arranged at an angle opposed to the angle of the vanes of the next adjacent row for producing miniature currents flowing in opposite directions.

2. In a papermaking machine, a homogenizing unit for producing organized cross currents capable of dispersing fibers in a flow box flow stream comprising, a rotatable roll disposed in and transversely of the flow box flow stream, a plurality of vanes rigidly fixed to and extending outwardly of the periphery of and obliquely to the longitudinal axis of said roll, the vanes of said plurality thereof being arranged in rows with the vanes of each row being parallel to each other and with the rows being axiallyspaced and equidistant from each other to divide the surface area of said roll into a plurality of substantially equal segmental sections, the vanes of a segmental section being arranged at an angle opposed to the angle of the vanes of the next adjacent segmental section for producing miniature currents flowing in opposite directions.

3. A homogenizing unit for the head box of a papermaking machine comprising, a rotatable hollow shaft, a multiplicity of radially-arranged outwardly-extending agitator blades stationarily secured to the outer periphery of said shaft, each such agitator blade being disposed obliquely relative to the longitudinal shaft axis and being pitched so as to be helicoidally directed, the blades being arranged as groupments with the blades of each groupment being arranged in a longitudinally-extending row in equi-spaced distance from each other and parallel relationship as to each other, with the axis of the row being parallel to the longitudinal axis of the shaft, each blade 10 of each row encompassing a divergence angle by virtue of its oblique disposition relative to the shaft axis, the divergence angle being between 45 and 89 relative to the longitudinal shaft axis.

References Cited by the Examiner UNITED STATES PATENTS 2,894,581 7/1959 Goumeniouk 162-339 2,934,142 4/1960 Ikavalko 162-342 X 3,074,476 1/1963 Corbin et a1. 162-342 3,104,999 9/1963 Sloman 162-342 X FOREIGN PATENTS 616,209 7/ 1935 Germany. 440,431 12/1935 Great Britain.

DONALL H. SYLVESTER, Primary Examiner. 

1. IN A PAPERMAKING MACHINE, A HOMOGENIZING UNIT DISPOSABLE WITHIN A FLOW BOX FOR PRODUCING ORGANIZED CROSS CURRENTS FOR DISPERSING THE FIBERS IN A FLOW BOX FLOW STREAM COMPRISING, A ROTATABLE ROLL DISPOSED IN SPACED RELATIONSHIP TRANSVERSELY OF THE FLOW STREAM IN THE HEAD BOX, A PLURALITY OF VANES REIGIDLY FIXED UPON SAID ROLL AND ARRANGED IN PARALLELISM OBLIQUE TO THE LONGITUDINAL AXIS OF SAID ROLL AND AXIALLY SPACED THEREALONG AS SETS IN ROWS EQUI-DISTANT FROM EACH OTHER, WITH THE VANES OF A ROW BEING ARRANGED AT AN ANGLE OPPOSED TO THE ANGLE OF THE VANES OF THE NEXT ADJACENT ROW FOR PRODUCING MINIATURE CURRENTS FLOWING IN OPPOSITE DIRECTIONS. 